Rationally designed nitrogen-doped carbon macroporous fibers with loading of single cobalt sites for efficient aqueous Zn-CO2 batteries

Abstract

Atomically dispersed metal catalysts supported on the rigidly hollow matrix are promising materials for developing carbon-neutral technologies. Herein, we develop an elaborate multistep templating approach to fabricate cobalt single-atom-decorated nitrogen-doped carbon macroporous fibers (Co SAs@NCMFs). During the thermal reduction, the cobalt nanoparticles derived from the sintered Co 2+ ions are formed at 600°C, which can be further transformed into unevenly loaded atomically dispersed cobalt sites at 1,000°C. The Co SAs@NCMF catalyst delivers excellent CO Faradaic efficiency (98.4%) and turnover frequency (38,390 h −1 ) at −1.0 V versus reversible hydrogen electrode for CO 2 electroreduction. Furthermore, benefiting from the multiple advantageous features, including rigidly hollow structure, high specific surface area, and accessible active sites, the Co SAs@NCMF electrode shows outstanding rechargeability and stable cycle life in aqueous Zn-CO 2 batteries. • An elaborate strategy is developed for preparation of single-atom catalysts • Cobalt single atoms are decorated on nitrogen-doped carbon macroporous fibers • The evolution pathway of Co species during pyrolysis is studied in detail • The electrode shows outstanding performance in aqueous Zn-CO 2 batteries Electrolyzing CO 2 into value-added chemicals by using renewable electricity provides an elegant way to re-balance the anthropogenic carbon cycle. Integrated with the zinc dissolution/deposition reaction, CO 2 electroreduction reaction can be applied in aqueous Zn-CO 2 batteries (AZCBs), which can simultaneously achieve CO 2 conversion and energy output. However, the cathode materials of AZCBs are still not satisfactory for practical applications. So far, considerable effort has been dedicated to developing advanced cathode materials for AZCBs. Among them, single-atom catalysts have become a promising candidate for AZCBs. Herein, we develop an elaborate approach to synthesize single-atomic Co sites distributed on nitrogen-doped carbon macroporous fibers. Benefiting from the multiple advantageous features, including rigidly hollow structure, high specific surface area, and accessible active sites, the prepared electrode shows outstanding rechargeability and stable cycle life in AZCBs. Single-cobalt-atom-decorated nitrogen-doped carbon macroporous fibers (Co SAs@NCMF) are rationally designed and synthesized through an elaborate multistep templating approach. Benefiting from the multiple advantageous features, including rigidly hollow structure, high specific surface area, and accessible active sites, the Co SAs@NCMF electrode shows outstanding rechargeability and stable cycle life in aqueous Zn-CO 2 batteries.